This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
In various medical modalities, a powered injector is used to inject the patient with a medical fluid, such as a drug, a contrast agent, a radiopharmaceutical, or a combination thereof. A typical powered injector includes a motor that drives a ram, which in turn drives a plunger of a syringe. Unfortunately, the motor and other electronics in the powerhead typically emit radiofrequency (RF) radiation that can detrimentally affect operation of medical equipment, such as a magnetic resonance imaging (MRI) system. In addition, the medical equipment, such as the MRI system, typically emits RF radiation that can detrimentally affect operation of the powerhead. Although existing powered injectors for MRI applications typically include radiation shielding, the detrimental affects of RF radiation can still hinder proper functioning of both the powerhead and the medical equipment.
In addition to the problems with RF radiation, existing powered injectors are generally too large, awkward, or inconvenient to place with the patient inside the magnet bore of the MRI system. Instead, the powerhead is placed outside the magnet bore, and a long run of tubing is used to connect the syringe tip with the injection site. A normal length of tubing may range from about 60 to 90 inches, and may contain as much as 4 to 5 milliliters of fluid. Unfortunately, this volume of fluid remains within the tubing after injecting the fluid from within the syringe, because movement of the syringe plunger cannot inject it into the patient. A typical MRI protocol may prescribe 20 milliliters of contrast agent, leaving about 4 to 5 milliliters of contrast agent (25 percent) within the tubing after the injection. A shortage of 25 percent of the prescribed contrast agent may hinder the image enhancement. MRI contrast agent, such as gadolinium, is very expensive and may be considered cost prohibitive to waste 4 to 5 milliliters of contrast agent per procedure. Existing MRI injectors typically have a second syringe that is filled with a flushing solution, such as saline. At the completion of the contrast injection, the injector chases the contrast agent down the tubing with the saline. This method ensures that the entire volume of contrast agent has been injected into the patient. Thus, only 4 to 5 milliliters of saline has been wasted, which is significantly less expensive than the MRI contrast agent. Unfortunately, the injected volume of saline does not offer any imaging benefits to the patient, while also adding complication, costs, and time to the procedure.